1. Field Of The Invention
This invention relates generally to valves, specifically throttle disc valves for maintaining required parameters in industrial processes, e.g., in heat power engineering at power plants for regulating feedwater discharge in a steam generator.
2. Prior Art
A prior art regulation disc valve with an external discharging device (SU 731163, 1978) works with a pressure differential of up to 20 MPa. The valve design is too complicated for production and servicing, which makes it less reliable. It also has limited flow capacity.
Another regulation disc valve with an internal discharging device (SU 987257, 1983) comprises a body containing a fixed seat with peripheral ports and a central channel. The fixed seat is in constant contact against a slide, which has notches. The slide is connected to a spindle and cylinder, and communicates with an intake chamber and a drainage chamber. A piston positioned in the cylinder cooperates with the cylinder to form a discharge chamber. The shortcomings include complicated design, insufficient reliability, and limited flow capacity.
A considerable shortcoming of these and other discharging type disc valves is the poor relationship between the slide-to-seat clamping force and off-loading force during valve opening and when the port area changes. This may result in the slide breaking away from the seat, an uncontrolled increase of the working medium flow rate, vibration, and premature failure.